[R] difference between 2 ecdfs
David Winsemius
dwinsemius at comcast.net
Sat Mar 22 01:50:45 CET 2008
In article
<0FF736F1E306A446A88FD41FDDDC10AF1C77B0 at BWPW05.f2.enterprise>,
<Erwann.Rogard at sanofi-aventis.com> wrote:
> hi,
>
> a) i have something like:
>
> ecdfgrp1<-ecdf(subset(mydata,TMT_GRP==1)$Y);
>
> ecdfgrp2<-ecdf(subset(mydata,TMT_GRP==2)$Y);
>
> how can i plot the difference between these 2 step functions?
>
> i could begin with ecdfrefl<-function(x){ecdfgrp2(x)-ecdfgrp1(x);} ...
> what next?
>
#not tested ...mydata not provided
ecrange<-range(mydata$Y)
plot(ecdfrefl(seq(from=ecrange[1],to=ecrange[2],by=0.2))
> b) if i have a vector with repeated numeric values how can i get the
> subset without repeated values .e.g (0,4,0,2,2) ----> (0,4,2) ?
>
?unique
> ttt<-c(1,3,5,5,5,7)
> unique(ttt)
[1] 1 3 5 7
--
David Winsemius
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